1. Field of the Invention
The present invention relates to a friction clutch used for power transfer of various machines and an automatic transmission of an automobile using the friction clutch and a non-stage transmission of an automobile and a power distribution device of an automobile and a power transmission device of a motorcycle.
2. Description of the Prior Art
Previously, as a clutch used for various power transfer mechanisms, a so-called multiple disk clutch has been well known, in which a lot of clutch plates rotating integrally with a member on the input side and a lot of clutch plates rotating integrally with a member on the output side are alternately arranged, and the respective clutch plates are pressed onto each other, so that the torque on the input side may be transferred to the output side by frictional force of each clutch plate.
This multiple disk clutch is widely used for an automatic transmission of an automobile, a non-stage transmission of an automobile, a power distribution device of an automobile, and a power transmission device of a motorcycle or the like, since the respective fellow clutch plates can be connected while being properly slid.
For example, in a general automatic transmission of an automobile, the rotational ratio of the output shaft to the input shaft is changed step by step by changing the combination of a lot of gears making up the power transmission passage, and therefore, by using a plurality of multiple disk clutches as a mechanism for arbitrarily regulating the rotation of a specific gear at the time of changing speed, the shock of speed changing is relieved by utilizing sliding when connecting each multiple disk clutch.
Furthermore, a non-stage transmission which is put in practice in part of automobiles is configured so that the speed may be continuously changed by using a pair of variable diameter pulleys and a V-belt. In this case, by using a multiple disk clutch as a starting clutch, an effective creeping (state where a little power is transmitted to the drive wheel side without pressing down the accelerator) is generated at the starting time by utilizing sliding of the multiple disk clutch.
Furthermore, as a power distribution device of an automobile, a device is well known, in which normally, the power of an engine is transmitted to a drive shaft on the front wheel side or the rear wheel side to perform two-wheel drive, and according to the running state or the like, the drive force is transmitted to both drive shafts on the front wheel side and the rear wheel side, respectively to perform four-wheel drive. In this case, when performing four-wheel drive, each of the drive shafts on the front wheel side and the rear wheel side is connected by a multiple disk clutch, and by utilizing sliding of the multiple disk clutch, the torque distribution to the front wheel side or the rear wheel side is controlled.
Furthermore, in a power transmission device of a motorcycle, the weight of the vehicle body is light relative to the maximum power of the engine, and therefore, by using a so-called wet multiple disk clutch, a sudden transmission of the power when starting is prevented by sliding of the respective fellow clutch plates.
However, in the above described multiple disk clutch, there are many cases where each clutch plate is used while being slid, and therefore, in the sliding state, the oil film between the respective clutch plates is cut off so that the clutch plate may easily wear away, which is disadvantageous in durability. Therefore, in an automatic transmission using gears, the sliding state of the clutch plate is reduced in the connection of the clutch at the time of changing speed, but since the torque is transmitted suddenly according to the decrease of the state of sliding, there has been such a problem that the shock of speed changing cannot be sufficiently relieved. Furthermore, in a non-stage transmission using a multiple disk clutch for starting, in order to decrease the wear of the clutch plate, the thrust force of the fellow clutch plates when a creeping occurs is reduced, and therefore, when compared with an automatic transmission using a torque converter, at present, it is a limit to generate a creeping force of approximately half degree thereof, which has been practically disadvantageous. Furthermore, in a power distribution device of an automobile, it is also necessary to continuously slide the clutch plate when controlling the torque distribution, and therefore, there has been a problem of easily generating the wear of a clutch plate. Furthermore, in a power transmission device of a motorcycle, since the clutch operation is artificially performed, the life of a clutch plate is shortened in the situation of frequently performing half-clutch, and there has been a problem of increasing the frequency of replacement and repair.
The present invention is achieved due to the above described problems, and it is an object of the present invention to provide a friction clutch capable of decreasing the wear in the sliding state and an automatic transmission of an automobile using the friction clutch and a non-stage transmission of an automobile and a power distribution device of an automobile and a power transmission device of a motorcycle.
In order to attain the above described object, a friction clutch of the present invention comprises: a pair of clutch members which are coaxially and relatively rotatably arranged with the peripheral surfaces opposite to each other in the radial direction and in which the respective opposite surfaces are formed to be inclined from one end side toward the other end side in the axial direction; a lot of rollers which are arranged between the opposite surfaces of the respective clutch members; a holder which rotatably holds each roller mutually at intervals in the circumferential direction of each clutch member; and thrust means which can thrust in the axial direction at least one of the respective clutch members in the direction in which the opposite surfaces of the respective clutch members approach each other, wherein the turning axis of each roller is inclined to have a specific angle relative to the rotation axis of the clutch member and in the meantime, the inclination angle thereof is made more than 10xc2x0 and less than 20xc2x0, and the turning axis of each roller is each inclined in the same direction to have a specific angle relative to the plane including the rotation axis of the clutch member and in the meantime, the inclination angle thereof is made more than 25xc2x0 and less than 90xc2x0.
According to this configuration, when a load in the axial direction is applied to each clutch member by the thrust means and each clutch member is relatively rotated while being brought into contact with each roller, each roller which tends to turn in the direction inclined relative to the rotary track of the clutch member turns along the rotary track of the clutch member while being restricted by the holder, and therefore, a frictional force by the sliding and turning of each roller is generated between each roller and each clutch member. At that moment, in one rotational direction of the clutch member, each roller tends to turn in one axial direction of the clutch member, and in the other rotational direction of the clutch member, each roller tends to turn in the other axial direction of the clutch member, and therefore, different frictional forces are generated depending on the rotational direction of the clutch member, respectively. In this case, by making the inclination angle of the turning axis of each roller relative to the rotation axis of the clutch member more than 10xc2x0 and less than 20xc2x0 and the inclination angle of the turning axis of each roller relative to the plane including the rotation axis of the clutch member more than 25xc2x0 and less than 90xc2x0, an effective and stable frictional force is generated at all times. As a result of this, the wear can be made extremely smaller than that of the structure in which the respective fellow clutch plates are brought into surface contact with each other like a multiple disk clutch, and the durability can be remarkably improved. Furthermore, since different frictional forces can be generated depending on the rotational directions of the clutch member, respectively, it is very advantageous in a case where such an operation is the object.
Furthermore, in order to attain the above described object, the friction clutch of the present invention comprises: a pair of clutch members which are coaxially and relatively rotatably arranged with the peripheral surfaces opposite to each other in the radial direction and in which the respective opposite surfaces are formed to be inclined from one end side toward the other end side in the axial direction; a lot of rollers which are arranged between the opposite surfaces of the respective clutch members; a holder which rotatably holds each roller mutually at intervals in the circumferential direction of each clutch member; and thrust means which can thrust in the axial direction at least one of the respective clutch members in the direction in which the opposite surfaces of the respective clutch members approach each other, wherein the turning axis of each roller is inclined to have a specific angle relative to the rotation axis of the clutch member and in the meantime, the inclination angle thereof is made more than 3xc2x0 and less than 8xc2x0, and the turning axes of the respective rollers are inclined in the opposite directions to: have a specific angle relative to the plane including the rotation axis. of the clutch member, a specific number of pieces by a specific number of pieces and in the meantime, the inclination angle thereof is made more than 25xc2x0 and less than 90xc2x0.
According to this configuration, when a load in the axial direction is applied to each clutch member by the thrust means and each clutch member is relatively rotated while being brought into contact with each roller, each roller which tends to turn in the direction inclined relative to the rotary track of the clutch member turns along the rotary track of the clutch member while being restricted by the holder, and therefore, a frictional force by the sliding and turning of each roller is generated between each roller and each clutch member. At that moment, when the clutch member is rotated in an arbitrary direction, part of rollers inclined mutually in the same direction tend to turn in one axial direction of the clutch member, and the rollers inclined in the other direction tend to turn in the other axial direction of the clutch member, and therefore, by the number of pieces of rollers inclined mutually in the opposite directions, it is possible to arbitrarily set the magnitude of the frictional force in each rotational direction of the clutch member. In this case, by making the inclination angle of the turning axis of each roller relative to the rotation axis of the clutch member more than 3xc2x0 and less than 8xc2x0 and the inclination angle of the turning axis of each roller relative to the plane including the rotation axis of the clutch member more than 25xc2x0 and less than 90xc2x0, an effective and stable frictional force is generated at all times. Consequently, similarly to the above description, the improvement of durability can be considerably attained, and in the meantime, it is possible to arbitrarily set the magnitude of the frictional force in each rotational direction of the clutch member, and therefore, it can be applied in a wide range according to the use.
Furthermore, in the above described friction clutch, the rollers inclined mutually in the opposite directions relative to the plane including the rotation axis of the above described clutch member are alternately arranged in the circumferential direction of the clutch member, by the same numbers, and consequently, an equal frictional force is generated regardless of the rotational direction of the clutch member. Accordingly, it is very advantageous in the case where such an operation is the object.
Furthermore, in the above described friction clutch, the above described respective clutch members are provided in the axial direction, in a plurality of pieces, and consequently, it is possible to arbitrarily set the magnitude of the frictional force according to the number of the respective clutch members. Accordingly, a frictional force complying with the object can be obtained.
Furthermore, in the above described friction clutch, the contact surface to the roller in the above described respective clutch members is each formed to be convex to the outer peripheral surface of the roller in the cross section including the turning axis of the roller, and consequently, it is possible to reduce the contact pressure on both end sides in the axial direction of each roller. Accordingly, the wear one-sided in the axial direction does not occur in each roller, and the durability of each roller can be improved.
Furthermore, in the above described friction clutch, the outer peripheral surface of the roller brought into contact with the above described respective clutch members is each formed to be convex to the contact surface of each clutch member in the cross section including the turning axis of the roller, and consequently, similarly to the above description, it is possible to decrease the contact pressure on both end sides in the axial direction of each roller, and the wear one-sided in the axial direction does not occur in each roller, and the durability of each roller can be improved.
Furthermore, in order to attain the above described object, the present invention is an automatic transmission of an automobile, comprising: an input shaft and an output shaft which are arranged mutually coaxially; a torque converter which transmits the power between the input shaft side and the engine side; at least one central gear which is arranged coaxially with; the input shaft and the output shaft; at least one pair of planetary,gears which are rotatably held by a holder rotatable around the input shaft and the output shaft and which are engaged with the central gear; at least one internal gear which is engaged with the planetary gear; a plurality of clutches which can regulate the relative rotation between specific members among an engine side member of the torque converter, the above described input shaft side member of the torque converter, the central gear, the holder of the planetary gear, the internal gear, and the transmission main body; and control means which each controls the connection and cut-off of each clutch according to the change of speed respectively, wherein a plurality of above described friction clutches are provided as the above described respective clutches, and each clutch member of each friction clutch is individually provided between specific members among the engine side member of the above described torque converter, the above described input shaft side member of the torque converter, the central gear, the holder of the planetary gear, the internal gear, and the transmission main body, and the thrust means of each friction clutch is controlled respectively by the above described control means. Consequently, when the above described clutch is connected while changing speed, each roller turns while sliding, so that a frictional force may be generated. As a result of this, the wear of each clutch can be extremely reduced, and it is possible to connect the clutch after continuing the sliding state of each clutch for a long time when changing speed. Accordingly, the shock in changing speed can be largely reduced.
Furthermore, in order to attain the above described object, the present invention is a non-stage transmission of an automobile, comprising: a first variable diameter pulley which rotates integrally with the input shaft; a second variable diameter pulley which rotates integrally with the output shaft; a belt which is wound up on each pulley; a starting clutch which is arranged between the output shaft and the drive wheel side; and control means which controls the connection and cut-off of the clutch, wherein the above described friction clutch is provided as the above described clutch, and one clutch member of the friction clutch is provided on the engine side and in the meantime, the other clutch member of the friction clutch is provided on the input shaft side, and. the thrust means of the friction clutch is controlled by the above described control means. Consequently, when the above described clutch is connected while transmitting the power of the output shaft to the drive wheel side, each roller turns while sliding, so that a frictional force may be generated. As a result of this, the wear of the clutch can be extremely reduced, and the sliding friction of the clutch can be increased when a creeping occurs. Accordingly, it is possible to obtain a practically sufficient creeping force.
Furthermore, the present invention is a power distribution device of an automobile, comprising: a clutch arranged between a drive shaft on the front wheel side and a drive shaft on the rear wheel side of an automobile; and control means for controlling the connection and cut-off of the clutch, so that the power of the engine to be transmitted to a drive shaft on the front wheel side or on the rear wheel side may be transmitted to both drive shafts on the front wheel side and on the rear wheel side by the connection of the above described clutch, wherein the above described friction clutch is provided as the above described clutch, and one clutch member of the friction clutch is provided to one of the drive shafts on the front wheel side and on the rear wheel side and in the meantime, the other clutch member of the friction clutch is provided to the other of the drive shafts on the front wheel side and on the rear wheel side, and the thrust means of the friction clutch is controlled by the above described control means. Consequently, when the above described clutch is connected while transmitting the power to both drive shafts on the front wheel side and on the rear wheel side, each roller turns while sliding, so that a frictional force may be generated. As a result of this, when distributing the power to the drive wheel on the front wheel side or on the rear wheel side, even in the case of arbitrarily controlling the torque distribution ratio by using the sliding of the clutch, the wear of the clutch can be extremely reduced. Accordingly, the improvement of durability can be attained.
Furthermore, the present invention is a power transmission device of a motorcycle having a clutch for intermittently transmitting the power of the engine to the drive wheel side by the operation of a clutch lever, wherein the above described friction clutch is provided as the above described clutch, and one clutch member of the friction clutch is provided on the engine side and in the meantime, the other clutch member of the friction clutch is provided on the drive wheel side, and the thrust means of the friction clutch is controlled by the above described clutch lever. Consequently, when the above described clutch is connected while transmitting the power of the engine to the drive wheel side, each roller turns while sliding, so that a frictional force may be generated. As a result of this, even in the case of often using the half-clutch when starting or changing speed, the wear of the clutch can be extremely reduced, and the improvement of durability can be attained. In this case, by making the setting so that the rotational direction of a larger frictional force may be on the acceleration side, the frictional force in deceleration can be reduced, and therefore, the excessive engine brake of, for example, a 4-cycle engine can be relieved, which is practically extremely effective.